Rotary compressor



March 23, 1954 |PKAU 2,6 73;027

ROTARY COMPRESSOR Filed Nov. 1, 1950 1 :5 sheets-sheet 1 ATTO R N EY5 March 23, 1954 p u 2,673,027

' ROTARY COMPRESSOR Filed Nov. 1, 1950 I5 Sheets-Sheet 2 INVENTOR' H.fl.L z' ojrau A BY g WT-TORNEYJ M r h 3, 1954 M. A. LIPKAU ROTARY COMPRESSOR 3 u t 2 m m m m k o S V T t NP T 9 l A m .0 s ,Y 3 L I I A H. M

Filed NOV. 1, 1950 Patented Mar. 23, 1954 UNITED STATES PATENT OFFICE.

ROTARY COMPRESSOR Maximiliano Alvarez Lipkau, Barcelona, Spain Application November 1, 1950, Serial No. 193,330

Claims priority, application Spain November 19, 1949 6 Claims. (Cl. 230-144) The present invention relates to rotary compressors for air or other gases, the mechanical construction and operation of which are completely distinct from those already known, and in which may be mentioned, as the principal advantage, the reduction in weight and size or volume obtained from the proportionally large increase in the effective volume of the cylinder and the simplicity of construction of the machine.

Other advantageous qualities to be mentioned are:

(a) The driving force and the resistance act in the same shaft;

(b) There is no transformation of the continuous circular movement of the motor;

() Practical suppression ,ofdead points;

(d) Maximum utilisation of .thekinetic energy of the compressor blades:

(-e) Suppression of the admission valve;

(1) Admission and compression in .a single cycle;

(g) Greater area in the deliveryand admission (suppression of throttling) (h) Improvements in the cooling;

(2') Reduction of dead spaces;

(9') Reduction in friction, as the blades are supported by the cylinder covers and do not, bear against the walls thereof.

Asa result thereis-a drop in the cost of manufacture due to the simplicity of the machine and itssmaller volume and weight (weight implying cost) and an economy in its operation. a

The invention is illustrated by way of example in the accompanying drawings of a concrete example of construction of the machine to facilitate the description, and reference will be made in the description-to these drawings, which are intended to afford the most exact and clear disclosure of the mechanism and operation of the machine; and hence, some positions of the parts in some of the figures vary with respect to the parts in others, so as to showwith greater clarity the relative positions of the parts.

In these drawings: 1

Figure 1 .is a longitudinal sectional view in which the relative position of the parts does not correspond to any one moment of operation, the position of some ofthe parts having been varied for the sake of clarity;

Figure 2 is a section on the line ,A A of Figure 1, in the direction of the arrows;

Figure 3 is a perspectiveof the two compressor e in P6 3933 s a to i be eni dea as to their nature and how they are mounted, one

2 of the blades extending over the shaft of the other;

Figure 4 is a view of a cover with its shockabsorber and the arm of the stopper piece;

Figure 5 is a viewof the relative position of the different parts of the impulsor-stopper mechanism corresponding to the position of the blades in Figure 2; v

Figure 6 comprises views of a blade given in conventional manner in order to show the closure or fluid-tight sealing rings of the same;

Figure 7 represents a possible form of the closure rings;

Figure 8 is a partial section on the line AA of Figure 1, similar to that of Figure 2 but showing another position of the blades;

Figure 9 is a view of the relative position of the various parts of the impulsor-stopper mechanism, corresponding to the position of the blades in Figure ,8;

Figure 10 is a partial section ofFigure 1 on the line'C-C, the gear [.5 and the part I! having been displaced to the right; and

Figure 11 represents the relative position of the parts of theimpulsor-stopper mechanism correspondingto the position of the blades in Figure 10.

Whenever the terms further back or further forward are used, referring to the blades, and according to how the machine is represented in the drawings, the direction of direct or clockwise rotation is meant.

The description of the machine and its operation may with the aid of these drawings be stated as follows:

Two blades l and 2 (Figure 3 and others) form an essential part of the machine, these being similar or symmetrical in form and substantially equal in weight, so that the uniformity of working of the machine is not varied, and comprising hubsor shafts I, 2', which are hollow so that they can pass over extensions on the closing covers of the cylinder which support them in overhun fashion, and can serve as a location for the rotating and stoppage mechanisms and arrangements. These hubs are approximately in length one half of the total length of the blade or vane, the latter extending beyond the hubs of the assembly in the manner shown inFigure 3. In order to produce a maximum fluid-tight sealing, the hubs ofithe two blades fit perfectly at their central portion and have rings 37!, 37' of rectangu lar form (Figure '7), which, when fitted intothe channelsof the blades, have antagonistic springs 38 hi dis ece -,them. a inst theinside asin or wall of the cylinder of the compressor, against the covers closing the same, and against the periphery of the hub of the other blade. The part of the ring that rubs against the covers is plane, and has a radius equal to that of the cylinder at the upper part which rubs against the latter, and is concave at the part that rubs against the periphery of the hub of the other blade. Instead of rings of rectangular shape, the sealing may be effected by means of two ground pieces 39, 39 as shown in Figure 6, that is, the actual blade is formed divided into two parts as far as its hub along a radial plane, and in the resulting slot a joint strip is arranged, which in its turn is divided into two parts obliquely, with springs 40 arranged at the dividing line, which tend to press the parts against the cylindrical casing, the ends of the cylinder, and the hub of the twin blade.

The said blades are located inside the cylinder (Figures 1 and 2), being concentric therewith and supported by extensions a of the covers 6 and 1 of the cylinder (Figure 1), which act as bearings or supporting trunnions, the hubs of both blades being overhung and perfectly fitting in extension. Inside the hubs thereof there are teeth b-b (Figures 1 and 2) for its actuation and stopping.

Reducing the weight of the blades is an advantage, for which reason they should preferably be constructed hollow and of aluminium or an aluminium alloy.

The cylinder 5 has in its casing an outlet valve 8 and admission or inlet ports 9 (Figure 2), and, at its ends, recesses for the closing covers 6 and I (Figure 1), which are fitted into the same and secured by means of bolts. Introduced into the cylinder are extensions a (Figure 1), which, as already mentioned, act as supporting bearings for the blades I and 2. These extensions are hollow and communicate with the outside so as to form a passage for a driving shaft II) and parts I! and I8. At their external part they have absorbers for the braking and stopping of the blades (Figure 4) and on the inside are located cam pieces 27 and 28 (Figure 1).

Passing right through the cylinder and its covers is the driving shaft Ill (Figure 1), supported by bearings II and I2, located in casings I 3 and I I, though in the case of small compressors these bearings may be omitted, the shaft It then being supported in parts I? and I3, and these in turn in the extended parts of the covers. At its central part is the driving gear wheel I5, which has teeth at every 45 degrees, which is the distance between the teeth of bb of the blades (Figure 2) when these are joined. This gear I5 has two keys I6 (Figures 1 and 2) fixed thereto, which are displaced axially therewith on this shaft in the keyways IE5 (Figure 1) formed in the shaft I0. Thus the said gear I5 has two movements, one a movement of rotation integrally with the driving shaft, and the other an axial movement upon the shaft. On both sides of the gear I5, arranged oppositely, are parts I1 and I8 (Fig ure 1) which have teeth I9 and 20. These parts extend to the exterior of the closing covers of the cylinder and have levers 2| and 22 fixed to them, which, on being applied to the pistons of the absorbers 23 and 24, only allow these a small rotary movement corresponding to the movement which the piston 25 (Figure 4) imparts. It must always be borne in mind when interpreting the mechanisms of Figures 5, 9 and 11 that the parts I1 and I8 do not rotate with the shaft I0, and that they can only be displaced axially in a reciprocating movement in order to come into or 4 leave the orbits of the teeth b-b of the blades I and 2 at the moments or during the exact times for immobilising them or leaving them free.

The exact arresting point of the blades can be adjusted by means of a screw 24 (Figure 4) for each absorber.

These absorbers consist (Figure 4) of a cylinder 24 cast on the cover, a piston 25, a spring 26, a shock-absorbing substance and an advancing screw 24'.

When the blade is liberated from its arresting mechanism, the piston of the shock-absorber rises through the action of the spring 26, raising the lever 2| as far as its stop. This causes the teeth I 9 and 26 (Figures 2 and 5) to be displaced (in the opposite direction to that of the rotation of the machine) from the position where they have to leave the blade arrested. For example: in Figure 2 is may be seen that the arresting tooth 20 occupied at the beginning of the position 0, establishing contact with the tooth b at this point e and then rotating as far as c. The result is thereby obtained that the teeth I9 and 2!) of the parts I! and I8 (Figure 5) establish contact with the teeth bb of the blades before the position at which it has to stop finally, whereby a greater smoothness is obtained in the absorption of the residual kinetic energy of the blades.

In large compressors, where this kinetic energy may be great, the absorbers will be hydraulic, and will be used for the pressure lubrication of the machine. The axial to-and-fro movements, at the moments and during the times necessary, are given to the driving gear I5 and arresting parts I! and It by lateral cams 2'1 and 23 located in the covers of the cylinder, the lateral profiles of these cams being followed by pusher members 29, 29, 3B and 30 (Figure 5). Each blade has two pusher elements, one for acting on the driving shaft I5 and another for acting on its arresting piece, to which they give the axial movement previously mentioned. In compressors of large displacement the said pusher members may be omitted, by arranging that the cams 21 and 28, fixed in the interior of the blades I and 2, shall act directly on the parts I5, I! and I8, acting at the same point where the pusher members act.

Between opposite pushers there is a key I5, which can slide in a corresponding keyway in the driving shaft, and which transmits the thrust of one pusher member to the opposite one. The said keyway, although it cannot be seen in the drawing in Figure 1, has to be longer than the key by an amount at least equal to the displacement of the said pusher members or rods.

The operation of the pusher members and the blades in the admission-compression cycle is as follows:

Figure 2: The blade I is displaced in the direct sense, whilst the blade 2 is stopped between the valve 8 and the ports 9. In this displacement air enters through the ports 9 and passes in a compressed state through the valve 8. In this figure it is possible to see clearly how the driving gear I5 actuates the teeth b integral with the blade I.

As mentioned, each blade is provided in its hub part with two rods or pusher members 29, 29 (Figure 2), which are able to slide axially in their locations in the hubs of the blades. In some cases these pusher members may have springs which maintain them constantly against the outline of the cams 21 and 28 (Figure 1) fibre rings then b'einginterposed on both sides of the gear l and in the portions of the parts l1 and 18 where these 'pushers are acting. By means of the blades they are carried along in their rotary translatory movement, following the outline of the cams of cylindricalformer-bottomthrust ramps 21 and 28. 7

Thus when the blade 1 (Figure 2) arrives in its movement of rotation at 45 degrees from blade 2, the'positions of the parts comprising the impulsor-arresting mechanism will be those shown in Figure 5. -The pusher member 29 of the blade under rotation will have arrived at the start of the incline of the cam 28, while the pusher member 29' of the driving gear "I5 will be positioned forty-five degrees further back. Meanwhile the pusher members BU-30 of the arrested blade 2 will also be-arrested in the same position in which they were in the previous cycle, when their blade, having terminated its movement of rotation, was arrested. Theblade l, continuing its movement, arrives ashort distance away from the arrested blade 2 (as may be seen in Figure 8) and the parts comprising the impulsor-arresting mechanism are situated inthe position shown in Figure 9; or

The pushmember .29 will have already arrived at the maximum part of the cam 28, and will have become displaced axially, pushing the part 11,:the teeth 20 of which (Figure 9) will enter the orbit of the teeth b (Figure 8) of the blade I, which will'be situated forty-five degrees further back (or they will have to cover almost forty-five degrees before the two teeth establish contact). The part I! in its axial displacement will displace the parts (Figures 1 and 2), which in their turn will do the same to the part l8 (Figure 9), the blade 2 thus becoming disengaged or free.

The parts l5 "slide along keyways formed in the shaft It and through the gear l5.

The blade 2, being freed from the teeth it (Figure 9) which immobilised it, will start moving owing to the action of the air which will have become compressed without any possible outlet in the space between the blades, and the blades will rotate together since the driving gear l5 will continue to actuatethe blade I until it arrives a little in front of the place which the blade 2 was occupying, at which as mentioned before, teeth 29 are already in position. During the period when both blades are rotating together, according to the pressure of the fluid in the said space between the blades, the blade 2, which is free, will accelerate or retard, increasing or reducing this space between the blades, with a consequent lowering or increase in pressure of the fluid accumulated, so that the blade 2 will take on the exact velocity of the blade I after a short travel under these conditions. The blades instantly obey any variation of pressure, as their area is very large compared with their weight. In a compressor having blades of about seventy square centimetres in area, for example, the weight of these does not reach five hundred grammes, whereas a force of seventy kilogrammes acts on their area for every kilogramme per square centimetre of increase in pressure. The space between the blades must therefore be very small, so that it becomes very sensitive to any variation in volume.

It can thus be seen that on the part l8 being forced (Figure 9) to disengage from the teeth I) of the blade 2 (Figure 8) the pusher memteeth b-b' of the'blades .l and .2.

. '6 ber 30 (Figure 9) willbe made to establishcontact with the cam l1.

Owing to the fact that the teeth :ofthe parts I! and I8 have to withdraw at the moment when there is a maximum amount of pressure on the blades, their teeth lllzand zllandxthe teeth b--'b of the blades are given, at the part whichengages, a slight inclination, which'facilitates disengagement.

After traversing together a sector of about forty-five degrees, the blades will be in the position of Figure 10, thepositionsof the parts .of the impulsor-arresting mechanism being those shown in Figure 11, or in other wordsthe pusher member-29 will have caused the gear [5 to pass from one blade to the'other, whilst they are'rotating together.

Figure 8 illustrates the relative positions of the In thisposition the gear 15 is displaced axially from one tooth to the other, leaving one and engaging the other simultaneously at the end ofits axial-travel.

It will be noticed that theair in the space between the blades acts :by imparting rotation to the blade 2 and opposing the advance of the blade l, so that when the gear 15 leaves the blade I, the latter will be braked by this :air and by its own friction until itisarrested by the immobilising teeth Ml.

With the blade I haltedan'd-the blade2 in rotation, the cycle will be repeated-in the same way as has already been explained; the blade which was previously stopped will "bein rotation, and vice versa. It can be seen from Figure ll'that the position of the parts!!! and 29' is the same as that of the parts '3iland 30 in Figure 5.

Lubrication is eifected'by splashing, which is produced by the parts 3 and '4 (Figure l), which effect the filling of the receptacles 35 and =36,

from which the oil passes into the cylinder through the passages 33 in'the partthat corresponds to the admission, the passage being adjusted'by-means of needle valves 3| and 32. The rest of the machine is-lubricated by circulation between the parts I! and I8 and thebodies of the closing covers of the cylinder.

The cooling is produced automatically by the circulating fluid itself. If necessary additional cooling by water or any other known medium may be provided.

For the rest, everything of accessory or circumstantial nature relatively to what forms the essentials in the said compressor, may vary, and the drawings and constructional details given must not be taken as a restricting the invention to one concrete example of construction of the new compressor but merely as explanatory and as being given for the sake of clarity.

I claim:

1. In a rotary compressor, the combination of a cylindrical casing having an inlet port and an outlet port; a pair of cover plates mounted on the ends of said casing, respectively, for closing said casing; a pair of hollow trunnions mounted on said plates, respectively, in said casing concentric therewith; a driving shaft passing through said trunnions and journaled in said casing; a, pair of driven shafts journaled on said trunnions, respectively; means for connecting and disconnecting said driving shaft, alternately, with said driven shafts; and a pair of compressor blades mounted on said driven shafts, respectively, each of said blades extending axially of its shaft over the other shaft, and extending radially from its shaft to said casini.

the ends of said blades extending to said plates, respectively, and the peripheral edges of said blades extending to said casing, said blades dividing the space between said driven shafts and said easing into two chambers of variable volume.

2. A rotary compressor as claimed in claim 1 in which the driven shafts are hollow, are mounted in an over-hung manner on the trunnions, and fit one into the other at their inner ends without affecting their ability to rotate independently of each other, said driven shafts forming with their facing hollow parts a space, the compressor has arresting and impulsor mechanisms located in said space. and also has internal projections on said shafts, with which the impulsor mechanisms gear and upon which the arresting mechanisms act.

3. A rotary compressor as claimed in claim 1, in which said means comprises a gear wheel mounted on the driving shaft inside the driven shafts of the blades, the said gear wheel being mounted on the driving shaft by means of keys which allow its free axial translation, so that by imparting to it an axial movement it gears alternately with the driven shafts.

4. A rotary compressor as claimed in claim 1, in which each of said driven shafts has an inside space and inside teeth, and said means comprises two tubular elements for said blades, respectively mounted in opposite manner on the driving shaft and extending from outside the end cover plates of the cylinder until their inner ends reach the inside spaces of the driven shafts, the said tubular elements being displaceable axially in relation to the driving shaft and not rotatable therewith, and having at their inside ends a number of peripheral projections which act as arrestors for the inside teeth of the driven shafts, liberating and arresting those of one and the other blade alternately, according as they are interposed into their orbit or not, by virtue of an axial movement which is imparted to the said tubular elements.

5. A rotary compressor as claimed in claim 1, in which said means comprises a gear wheel on the driven shaft, tubular elements in the plates, arrestors on the plates and a plurality of rods located in corresponding bores parallel to the driving shaft eccentrically with respect thereto, provided for the purpose in said driven shafts,

the said rods having free axial movement and being carried along by the rotation of their corresponding blades, and the said rods acting in their axial direction by pressure upon said gear Wheel and upon said tubular elements, upon one of them directly and upon the other through the medium of a key stop or abutment arranged between the two and sliding freely into a longitudinal groove in the driving shaft, the said rods being controlled by cylindrical cams fixed to the end cover plates of the cylinder and disposed therein along the circular path described by the rods in their cylindrical translation, so that the external ends of these rods engage the said cams, thus becoming displaced axially, and the inside ends of the same transmit these displacements laterally to said gear wheel and to said arrestors. which in turn push the rods of the other side, which yield, this cycle being repeated successively and alternately for the rods of either side, and finally determining an axial reciprocating movement for the same and consequently for the gear wheel and the arrestors.

6. A rotary compressor as claimed in claim 1 in which fluidtight closure of the blades is obtained by providing in each blade along a radial plane a slot which extends as far as the driven shaft, and disposing in said slot a joint plate divided obliquely into two parts, with opposing springs between said parts, which bias said parts against the casing and end plates and against the driven shaft of the other blade.

MAXIMILIANO ALVAREZ LIPKAU.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 777,384 Mist Dec. 13, 1904 907,929 Thomas Mar. 28, 1911 1,928,994 Daw Oct. 3, 1933 2,222,706 English Nov. 26, 1940 2,367,676 Griffith Jan. 23, 1945 2,544,480 Bancroft Mar. 6, 1951 2,544,481 Bancroft Mar. 6, 1951 FOREIGN PATENTS Number Country Date 38,871 France May 11, 1931 (Addition to N0. 693,838) 

